Field of the Invention
The present invention relates to an image forming apparatus such as a copying machine, a multifunction printer, or a facsimile machine, and particularly relates to an image forming apparatus having a power-saving mode in which the apparatus is switched from a predetermined normal power consumption state into a low power consumption state where less energy is supplied than in the normal power consumption state.
Related Art
For energy saving, an image forming apparatus such as a copying machine, a multifunction printer, or a facsimile machine may have a power-saving mode (which may be also called energy-saving mode or electricity-saving mode) in which the apparatus is switched from a predetermined normal power consumption state into a low power consumption state where less energy is supplied than in the normal power consumption state.
An image forming apparatus having a power-saving mode is configured to switch into the power-saving mode if one or more predetermined power-saving mode conditions are met (for example, if the image forming apparatus remains in a standby state for a predetermined time without interruption, and/or, if a motion sensor for detecting a person detects no person). In the power-saving mode, if one or more predetermined power-saving mode release conditions are met (for example, if a user effects a predetermined operation, and/or, if the motion sensor detects a person), the image forming apparatus is configured to return from the low power consumption state in the power-saving mode to the normal power consumption state.
When a conventional image forming apparatus having such a power-saving mode returns from the low power consumption state in the power-saving mode to the normal power consumption state, it is a common practice to execute control of a return operation for the image forming apparatus from the power-saving mode (for example, an initial operation, or an initialization operation, for a predetermined component such as a pick-up roller). Control of the return operation for the image forming apparatus from the power-saving mode is not necessarily obligatory, but is executed constantly in prior art, and constant execution of the control of the return operation for the image forming apparatus from the power-saving mode entails various inconveniences.
Such inconveniences are mentioned by taking, as an example, an image forming apparatus equipped with a sheet placing portion (specifically, a paper feed tray) on which one or more sheets (for example, at least one recording sheet such as a document or a piece of recording paper) are placed, and a sheet feeding apparatus (specifically, a paper feeder) having a pick-up roller which is configured to be capable of moving up and down and to feed the one or more sheets placed on the sheet placing portion, one by one, by moving down from a raised position. In the following exemplary cases, the return operation for the image forming apparatus from the power-saving mode is an initial operation for the pick-up roller.
In this image forming apparatus, if the pick-up roller stays at a lowered position unintentionally (for some reason) before a sheet is set on the sheet placing portion, it is difficult or even impossible to place a sheet on the sheet placing portion.
An example of unintentional descent of the pick-up roller is described by way of the following image forming apparatus. An image forming apparatus is composed of an image reading device having a moving document reading configuration in which an image on a document is read while the document, as the sheet, is caused to move. The image reading device has a document feeding device equipped with a pick-up roller. The document feeding device has, as an opening closing member, an opening closing guide member which is configured to be openable from and closable on a document feeding device main body and which is equipped with the pick-up roller. When the opening closing guide member is operated for opening and closing by a user, a drive connection member such as a gear which constitutes a drive transmission mechanism to the pick-up roller is caused to move away on opening, and/or the opening and closing operation causes vibration or the like. Such displacement and/or vibration causes the pick-up roller to move down from the raised position.
Another example of unintentional descent of the pick-up roller is described by way of the following image forming apparatus. An image forming apparatus is composed of an image reading device which includes not only the moving document reading configuration but also a stationary document reading configuration in which an image on a document is read while the document, as the sheet, is placed on a document placement stand. The image reading device has a document feeding device equipped with a pick-up roller, and a document reading device equipped with a document placement stand. The document feeding device, as an opening closing member, doubles as a document holddown member which is configured to be openable from and closable on the document reading device and, when closed, which holds down a document placed on the document placement stand. When the document feeding device is operated for opening and closing by a user, the opening and closing operation causes vibration or the like, and such vibration causes the pick-up roller to move down from the raised position.
Yet another example of unintentional descent of the pick-up roller is described by way of the following image forming apparatus. An image forming apparatus is composed of an image forming apparatus main body for forming an image. The image forming apparatus main body has a sheet placing portion (specifically, a paper feed tray) which is configured to be attachable to and detachable from the image forming apparatus main body and which places one or more recording sheets as the sheet(s). When the sheet placing portion is operated for opening and closing by a user, the opening and closing operation causes vibration or the like, and such vibration causes the pick-up roller to move down from the raised position.
Still another example of unintentional descent of the pick-up roller is described by way of the following image forming apparatus. An image forming apparatus has an image forming apparatus main body provided with an opening closing member which is configured to be openable from and closable on the image forming apparatus main body. When the opening closing member is operated for opening and closing by a user, a drive connection member such as a gear which constitutes a drive transmission mechanism to the pick-up roller is caused to move away on opening, and/or the opening and closing operation causes vibration or the like. Such displacement and/or vibration causes the pick-up roller to move down from the raised position. Examples of the opening closing member configured to be openable from and closable on the image forming apparatus main body include an opening closing cover member (for example, a front cover member which covers a front face of the main body) and an opening closing guide member (for example, a side guide member which covers a side face of the main body).
In order to solve these inconveniences, the conventional image forming apparatus executes control of an initial operation for the component (e.g. an initial operation of raising the pick-up roller to the raised position), for example, at the start-up of the image forming apparatus (including the reboot in the power-on state) or at the end of a job (a cycle of image forming operation). Further, as a detection unit for detecting the operating state of the image forming apparatus, the conventional image forming apparatus is provided with at least one detection unit for detecting whether the opening closing member is open or closed. When the detection result by the detection unit indicates that the opening closing member is open at first but closed later in the normal power consumption state, the image forming apparatus executes control of an initial operation (e.g. an initial operation of raising the pick-up roller to the raised position, assuming that the pick-up roller has moved down, or may have possibly moved down, from the raised position unintentionally due to an opening and closing operation of the opening closing member by a user). In these cases, the initial operation is, for example, to raise the pick-up roller by means of a motor or a solenoid.
The conventional image forming apparatus executes control of an initial operation to the component, as the control of the return operation for the image forming apparatus from the power-saving mode, also when the image forming apparatus returns from the low power consumption state in the power-saving mode to the normal power consumption state. In this case, when the image forming apparatus returns from the low power consumption state in the power-saving mode to the normal power consumption state, the conventional image forming apparatus constantly executes control of the initial operation, as the control of the return operation for the image forming apparatus from the power-saving mode, irrespective of whether the opening closing member is open or closed (namely, without detecting whether the opening closing member is open or closed in the power-saving mode).
As described, when the image forming apparatus returns from the low power consumption state in the power-saving mode to the normal power consumption state, the conventional image forming apparatus constantly executes control of the initial operation, as the control of the return operation for the image forming apparatus from the power-saving mode, irrespective of whether the opening closing member is open or closed. However, constant execution of the control of the return operation for the image forming apparatus from the power-saving mode entails various inconveniences: a user has to wait while control of the initial operation is executed; the noise of the initial operation for the component (for example, the noise of raising the pick-up roller) is annoying to the user; or, if the image forming apparatus is configured to return from the low power consumption state in the power-saving mode to the normal power consumption state when the presence of a person is detected by a detection result by the motion sensor, control of the initial operation is triggered by mere approach of a user to the image forming apparatus, which makes the user frustrated.
In order to minimize the initial operation in the document feeding device, the image forming apparatus disclosed in JP 2012-95242 A discloses does not basically perform control of an initial operation (see paragraph [0093] in JP 2012-95242 A). When the power-saving mode is cancelled, this image forming apparatus performs control of an initial operation, only if the cover (the opening closing member) of the document feeding device was open or in a certain state just before the image forming apparatus went into the power-saving mode (see paragraphs [0094], [0095], and [0099], and FIG. 7 in JP 2012-95242 A).
Nevertheless, the image forming apparatus disclosed in JP 2012-95242 A does not detect the operating state of the image forming apparatus (specifically, whether the opening closing member is open or closed) in the power-saving mode. Hence, this image forming apparatus cannot execute control of the return operation for the image forming apparatus from power-saving mode without fail, based on the operating state of the image forming apparatus in the power-saving mode.
In view of the above, the present invention aims to provide an image forming apparatus which can avoid inconveniences associated with constant execution of the control of the return operation for the image forming apparatus from the power-saving mode when the image forming apparatus returns from the low power consumption state in the power-saving mode to the normal power consumption state, and which can execute the control of the return operation for the image forming apparatus from the power-saving mode without fail, based on the operating state of the image forming apparatus in the power-saving mode.